Rotary fluid-pressure motor



M. P. HOLM ES PRESSURE uoToR ROTARY FLUID Filed Sept.

2 Sheets-Sheet 1 lvvven z or: 773077361-2120371085.

Dec. 1924- 1,520,242 M. P. HOLMES ROTARY FLUID PRESSURE MOTOR ed Sent. 26, l 9 l8 2 Sheets-Sheet- 2 J0 any;

Patented Dec. 23, 1924.

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MORRIS P. HOLMES, OF CLAREMONT, NEW HAMPSHIRE, ASSIGNOR T0 SULLIVAN MACHINERY COMPANY, A CORPORATION OF MASSACHUSETTS.

ROTARY FLUID-PRESSURE MOTOR.

Application med September 2c, 1918. I Serial No. 255,797.

To all whom it may concern:

Be it known that I, MORRIS P. HoLMEs, a citizen of the United States, residing at Claremont, in the county of Sullivan and L State of New Hampshire, have invented certain new and useful Improvements v in Rotary Fluid-Pressure M6tors,.of which the following is a full, clear, and exact specification. p

This invention relates to rotary fluid pressure motors, more particularly, although not exclusively, to compressed air motors, and has for its general object to provide an impro ed motor of this type which is of simple, inexpensive, and 1 compact high power in proportion to its size and weight, which may be readily assembled and disassembled, and'which is adapted to desembled relationship by means of bolts or screws 13. The central section 10 is formed with two parallel, intersecting, cylindrical rotor chambers 14 (Fig. 4) to receive the rotors, designated asa whole by the numeral 15, which are mounted on shafts 16 journaled, as hereinafter more fully described, in the end sections or heads 11 and 12.

The two rotors 15 are provided with intermeshing blades or teeth each comprising two oppositely inclined spiral end portions connected at their inner, ends by a short straight portion, as clearly shown in Fig. 1, thereby providing a double spiral or helical rotor couple ofa well known general type. For convenience in manufacture, each rotor is, in the present instance, composed of three connected sections, vi'z., two end sections, 17 and 18 as which are formed, respectively, the opposi ely inclined spiral tooth portions, and an intermediate section 19 on which are construction, which is capable/of developing a relatively formed the straight tooth portions, the outer ends of the latter registering with the inner ends of the respective spiral portions.

In rotors of this general type, as heretofore constructed, and comprising rotor sections having oppositely inclined teeth, it has been customary to key eachof the rotor sections to the rotor shaft, and considerable difficulty has been encountered in bringing the ends of the teeth on the several sections into exact register, as is essential to the proper operation of the device. It has usually been necessary, in assembling the rotor sections in this manner, after the angular positions of the sections have been fixed by their keys, to cutaway a greater or less 7 amount at the inner end of one or another of the sections and move the same longitudinally toward the adjacent section, so that this longitudinal fitting may supply the necessary angular increment to bring the ends of the teeth on the adjacent sections into exact circumferential register. This opera tion is not only a very delicate one, requiring great care and high skill, witha correspondingly high production expense, but results in an objectionable variation in the length of the completed rotors.

In accordance with the resent invention, these difiiculties and objeetlons are overcome by keying only one of the rotor sections, herein the sections 18, to the shaft 16, and

securing the remaining sections 17 and 19 thereto by means of longitudinally extending bolts 20, which not only serve to hold the several sections in assembled relationship, but also to secure the sections 17 and 19 to the shaft 16 for rotation therewith by reason of their attachment to the section 18 which is, in turn, keyed to said shaft. With this, construction, the section 18 may first be keyed tothe shaft and the other sections loosely assembled thereon and angularly adjusted relatively to the section 18 and to each other in order to bring the teeth thereon into exact register. The several sections may thereupon be clamped in this position and holes drilled for the bolts 20, which are inserted and tightened, thereby producing an accurately formed rotor in a simple manner and without shortening.

In order to reduce the total len h of the motor to a minimum, as is desira Is in the mining machines, in which economy of space is an important consideration, the outer ends of the rotor sections 17- and 18 are recessed, as shown in Fig. 3, to receive projections or bosses 21 formed on the end casing sections 11 and 12, said projections or bosses supporting the bearings for the shafts 16. As

herein shown, the bearings 22 for one end of each of the shafts are seated in sockets formed in the bosses 21 of the casing section 12, while the bearings -23 and 24 for the opposite ends of said shafts are located in bores extending through the bosses of the casing section 11, being retained therein by rings or washers 25 suitably secured to the exterior of said casing section, as by cap screws. Preferably the bearings 22 and 24 will be of a suitable and approved roller type, while the bearing 23 may be a double thrust ball bearing, secured by means of the usual nut or Washer 26, for taking up the end thrust, if any, of the two shafts, said thrust being communicated from one shaft to the other by the engagement of the teeth of the two rotors.

The referred arrangement of the pressure fluid ports and passages is. as follows. The end casing section or head 12 is formed adjacent its ends with two curved inlet passages 27 (F igs; 2 and 3) arranged at opposite sides of a central gear chamber 28, hereinafter referred to, said inlet passages communicating, through an opening 29 (Fi 2) in the inner wall of the casing section 12, with a pressure chamber 30 (Fig. 4) formed in the bottom of the central casing section 10 beneath and between the rotor chambers 14, said pressure chamber having a port 31 through which pressure fluid is admitted to the teeth of the rotors at a point substantially midway of the length of the latter, or opposite the straight toothed central rotor sections 19. One of the inlet passages 27 is provided at its upper end with a fluid pressure inlet 32 (Fig. 2) which may be connected with any suitable source of fluid pressure supply through a pipe or conduit 33 (Fig. 1) controlled by the usual throttle valve (not shown). At the upper end of the other inlet passage 27 is preferably provided an inwardly opening check valve 34 (Figs. 1 and 2),communicating with the atmosphere, whereby the inlet passages may be vented to prevent the formation of vacuum therein due to overrunning of the motor by momentum after the throttle valve is closed.

The walls of the rotor chambers 14 surround the rotors 15 with a closely engaging fit substantially throughout the, peripheries of the latter, and the exhaust from the rotor teeth takes place at the ends of the rotors through annular exhaust cavities 35 (Fig. 3) formed in the end casing sections 11 and 12 and surrounding the bosses 21. The exhaust raaoeae cavities 35 communicate with exhaust chambers 36 (Fig. 4) formed in the top of the central casing section 10 above the rotor chambers, said exhaust chambers being provided'with oil and dust traps 37 and discharging to the atmosphere through exhaust ports .or openings 38 in'the top wall of the casing. The arrangement described provides for a complete expansion of the motive fluid within the rotor chambers and a free exhaust thereof after such expansion, thereby resulting in a high efficiency and the development of a high degree of power in proportion to the size of the motor.

The ends of the rotor shafts 16 extend through the bearings 22 into the gear chamber 28 in the end casing section 12, and are there provided with transmission gears or pinions 39 (Fig. 3) splined or otherwise I mounted thereon for rotation therewith but movable longitudinally thereof, said pinions cooperating with a central transmission gear 40. It will be obvious that, since the rotors 15, and consequently the shafts 16, rotate in opposite directions, by engaging either one or the other of the pinions 39 with the gear 40, the latter may be caused to rotate in either direction. Any suitable gear shifting mechanism may be employed for alternatively moving the pinions 39 longitudinally of their shafts into and out of mesh with the gear 40. As herein shown, the pinions 39 are formed with grooved hubs 41 which are engaged by arms or levers 42 (Figs. 1 and 2) pivoted on studs 43 carried by a cover plate 44 secured by screws 45 over an opening in the top of the casing section 12 and removable to afford access to the gear chamber 28. Said cover plate is preferably provided with openings through which lubricant may be supplied to the gear chamber 28 and parts therein, said openings being closed by plugs 62. The levers 42 are formed with gear segments 46 which cooperate with a mutilated pinion 47 keyed to a stem 48 rotatably mounted in the cover plate 44 and provided outside the casing with an operating handle or knob 49. The arrangement is preferably such that, as the handle 49 is turned in one direction or the other from a central neutral position in which both of the pinions 39 are out of mesh with the gear 40, one or the other of the arms 42 will be swung on its pivot to move the corresponding pinion into mesh with said gear, the remaining arm being locked against movement.

. This particular gear shifting mechanism inl element 54 of the mechanism .to be actuatedthereby. The ear53 is retained on the shaft 51, and the hu 52 thereof clamped in place on the hub of the gear 40, by means of a nut 55 on the threaded end of said shaft, and said hub 52 is journaled in an anti-friction bearing 56 (preferably a roller bearing similar to the bearings 22 and 24) carried by a bushin 57 mounted in an opening in the wall of t e casing section 12. The opening 66 in the gear 53 is preferably of a somewhat greater diameter than the shaft 51 and is threaded, whereby a correspondingly threaded rod or bolt may be passed therethrough and into engagement with the end of the hub 50 to force said hub and gear apart in disassembling. The inner end of the shaft 51 is in threaded engagement with a sleeve 58 rotatably mounted in an antifriction bearing 59 (preferably a double thrust ball bearing similar to the bearing 23) held by a locking washer or ring 60 in an opening in a boss 61 projecting into the gear chamber 28 from the inner wall of the casing section 12, the inner end of said opening being closed by a cap 63 held in place by said bearing. The sleeve58 and hub 50 are connected by means of a pin 64 projecting from said hub and entering a. longitudinal interior groove in said sleeve, thereby permitting longitudinal movement of said hub with respect to saidsleeve while maintaining the connection of said parts for rotation in unison. The shaft 51 is provided with a flange 65 against which the end of the hub 50 is clamped when the nut 55 is tightened.

The connections last described constitute the subject matter of a divisional application, filed Oct. 2, 1924, Serial No. 741,214. These connections permit an axial adjustment of the transmission gear 40 with its connected driving gear 53 with respect to the bearing 59 and consequently with respect to the casing, this adjustment not being sufiicient, however, to disturb or prevent the operative engagement of the pinions 39 with said gear40. Such an adjustment is extremely convenient in a motor of this character which is employed as the power element of a unitary machine, inasmuch as the .positions of both the motor casing and the driven gear in the machine frame are usually fixed in any given machine but, by reason of variations in workmanship, are likely to differ slightly in different machines, so that some adjustment to insure proper engagement of the driving and driven gears is necessary or desirable, both in the initial setting of the parts and to compensate for subse uent wear. In the present machine, shoul adjustment of the driving gear 53 with respect to the driven gear 54 be re-- quired, the nut 55 is loosened, and the shaft 51 is turned by means of a screw driver applied to the-slotted end thereof, the gear 53, and consequently the hub 50 and sleeve 58, being held stationary, thereby by reason of the threaded engagement of said shaft with the sleeve 58, adjusting said shaft with the gears 40 and 53 in an axial direction. Thereafter the nut 55 is tightened, said nut serving both to retain the gear 53 in place on the hub of the gear 40 and to hold the shaft 51 against accidental turning in the sleeve 58 by clamping the flange 65 thereon against the hub 50.

In order toprevent the pressure fluid from the exhaust cavities 35 from reaching and passing through the bearings 22, 23, and 24 and the gear chamber 28, and thereby tending to blow the lubricant therefrom, the shafts 16 are provided intermediate their bearings and the exhaust cavities, and with- I in the bosses 21, with circumferential grooves 67 which communicate through ports 68 with axial passages 69 in said shafts which extend to the ends thereof at the exterior of the casing. Exhaust air passing along the shafts from the exhaust cavities will encounter the grooves 67 before reaching the bearings, and thence will be discharged through the ports 68 and passages 69 to the atmosphere.

While I have in this application specifically described one form which my invention may assume in practice, it will be understood that this form of the same has been shown for purposes of illustration and that the invention may be modified and embodied in various other forms without depart-in from its spirit or the scope of the appended claims.

What I claim as new and desire to secure by Letters Patent is:

1. In a fluid pressure motor, a casing having a rotor chamber, a pressure chamber below said rotor chamber and communicating therewith, an exhaust chamber above said rotor chamber and communicating therewith only through the ends thereof, an oil and dust trap in said exhaust chamber, and an exhaust port in the top of said casing leading from said exhaust chamber to the atmoiphere.

2. n a fluid pressure motor, a casing having a rotor chamber, end closures for said casing having exhaust cavities communicating with said rotor chamber, a gear chamber. formed on one of said end closures, and pressure fluid inlet passages extending around the. exterior of said gear chamber and communicating with said rotor chamber. i

3. In a fluid pressure motor, a casing having a plurality of rotor chambers, a pres sure chamber below and between said rotor chambers, and end closures for said casing having exhaust cavities communicating with said rotor chambers, one of said end closures having a gear chamber, and pressure fluid inlet passages extending around said gear chamber and communicating with said pressure chamber in said casing.

4. In a fluid pressure motor, a casing com prising a central section and end sections secured to said central section, each of said lattersections having rotor bearin s, said central section having a rotor cham er and pressure and. exhaust chambers, and one of said end sections having pressure and exhaust spaces communicating with said pressureand exhaust chambers, respectively.

'5. In a fluid pressure motor, a casingcomprising a central section and end sections secured to said central section, said central sec-' tion having a rotor chamber and an exhaust cavity, a rotor in said chamber, and rotor bearings disposed adjacent each of said end sections and at least one of said sections and the bearing adjacent thereto being removable to allow removal of said rotor and said end sections having exhaust" cavities oommunicating with the ends of said rotor chamber and with said exhaust cavity-in said central section. 4

6. In a fluid pressure motor, a casing comprismg a central section and end sections secured to said central section, each of saidlatter sections having rotor bearings each accessible from the end in which they are of said end sections having pressure and ex haust spaces communicating with said pressure and exhaust chambers, respectively.

7. In a fluid pressure motor, a casing comprising a central section, an end sectlon secured to said central section,-said central section having a rotor chamber and a pressure chamber and said end section having an exhaust cavity communicating with said rotor chamber, a gear chamber, and fluid inlet passages extending around said gear chamber and communicating with said pressure chamber.

8. A fluid pressure motor comprising a casing and a rotor therein, said casing having a branched inlet passage leading to said rotor, one of said branches being connected to a source of fluid pressure, the second having an inwardly opening check valve therein, and a branched exhaust connection in said casing leading from the ends of the rotor to the atmosphere.

9. In a fluid pressure motor, a casing having a rotor chamber, exhaust connections leading from the ends of said rotor chamber, a gear chamber at one end of said rotor rsaoaaa chamber, and a plurality of fluid inlet passages extending around said chamber and communicating with said rotor chamber, one of said passages leading to a source of fluid pressure and another of said passages having' an inwardly opening check valve communicating with the atmosphere.

10. In a fluid pressure motor, the combination with a casing having a substantially cylindrical rotor chamber, of a rotor in said chamber having recessed ends, bearings for, said rotor carried by the end walls of said chamber within the recessed ends of said rotor, and leakage connections between the bearings at opposite ends of the rotor and the atmosphere.

11. In a fluid pressure motor, the combination with a casing comprising a central section and two end sections secured to said central section, said central section having a rotor chamber and a pressure chamber communicating therewith, of a rotor in said rotor chamber having recessed ends, and bearings for said rotor carried b said end sections within the recessed en s. of said rotor, said bearin s having leakage vents communicating with each other and with the atmosphere.

12. In aliuid pressure motor, the combination with a casing having a rotor chamber provided with end walls, of a rotor in said chamber having recessed ends, the end walls of said rotor chamber being provided with bosses extending into the recessed ends of said rotor and with annular exhaust cavities surrounding said bosses, bearings for said rotor carried by said bosses, and means to prevent leakage from said exhaust cavities through said bearings.

13. In a {fluid pressure motor, the combination with a casinghaving a rotor chamber, of a rotor in said chamber, a shaft on which said rotor is mounted, anda bearin for said shaft, within the end wall of sai chamber, said shaft having a circumferential groove between said chamber and said bearing and a longitudinal passage communicating with said groove and extending to the exterior of said casing.

14. In a fluid pressure motor, the combination with a casing having a rotor chamber provided with endwalls, of a rotor in said chamber having recessed ends, a shaft on which said rotor is mounted, the end walls of said rotor chamber being provided with bosses extending into the,..recessed ends of said rotor and with annii'liir exhaust cavities surrounding s'aidbosses, and bearings for said shaft within said bosses, said shaft having circumferential grooves between said bearings and the inner ends of said bosses and a longitudinal passage communicating with said grooves and extending to the exterior of said casing.

15. In a fluid pressure motor, the combination with a shaft, of a multi-sectioned toothed rotor thereon comprising a. section fixed to said shaft and one .or more sections held in fixed relation with respect to said shaft only by a rigid connection to said first mentioned section, but fitting said shaft snugly.

16. In a fluid pressure motor, the combination with a shaft, of a multi-sectioned rotor thereon comprising a section having straight teeth and one or more sections provided with inclined spiral teeth, one of said sections being rigidly secured to said shaft and another secured to said last mentioned section, but not to said shaft, but being a snug fit therefor.

17. In a fluid pressure motor, the combination with a shaft, of a double spiral rotor thereon comprising a plurality of sections provided respectively with oppositely inclined spiral teeth, one of said sections being fixed to said shaft and another of said sections being loosely mounted on said shaft and rigidly secured to said firstnamed section, said shaft having bearing portions at opposite sides of said rotor.

18. In a fluid pressure motor, the combination with a shaft, of a double spiral rotor thereon comprising a plurality of sections provided respectively with oppositely inclined spiral teeth, one of said sections being fixed to said shaft and another of said sections being loosely mounted on said shaft, and one or more bolts for rigidly securing said sections together, said shaft extending completely through said rotor and having journal portions adjacent opposite ends thereof.

19.v The combination with a driven ele-- ment, of a motor comprising a casing, motor elements within said casing, a driving element carried by said casing and operatively connected with said motor elements and with said driven element, and means whereby said ment is carried, and means for retaining said driving element on said shaft and for re- 7 taining said shaft in adjusted position.

21. The combination with adriven element, of a motor comprising a casing, motor elements within said casing, a driving element opcrati'vely connected with said motor elements and with said driven element, a hearing within said casing havin a rotating member connected with said driving element for rotation therewith, said member and element being relatively longitudinally movable, and a shaft having threaded engagement with said rotating member whereby said shaft is longitudinally adjustable with respect to said member, said driving element being mounted on said shaft and longitudinally movable therewith.

22. The combination with a driven element, of a motor comprising a casing, motor elements within said casing, a driving element operatively connected with said motor elements and with said driven element, a bearing within said casing having a rotating member connected with said driving element for rotation therewith, said member and element being relatively longitudinally movable,'a shaft having threaded engagement with said rotating member whereby said shaft is longitudinally adjustable with respect to said member, said driving element being mounted on said shaft and lon 'tudinally movable therewith, and means or retaining said driving element on said shaft and for retaining said shaft in adjusted position.

23. The combination with a driven gear, of a motor comprising a casing, a rotor therein, a transmission gear operatively connected with said rotor and having a hub, a driving gear meshing with said driven gear and mounted on said hub for rotation therewith, a hearing within said casing, a sleeve journaled in said bearing and having a splined connection with said transmission gear, a shaft on which said transmission gear is rotatably mounted, said shaft havin a collar engaging the end of the hub of said transmission gear and having threaded engagement with said sleeve. whereby said shaft and the gears thereon are longitudinally adjustable and a nut on the end of said shaft and engaging said driving ear, whereby said driving gear is retame on said hub and said hub forced into engagement with the flange on said shaft to hold said shaft against turning in said sleeve.

In testimony whereof I afiix my signature.

MORRIS P. HOLMES. 

